Fibers, e.g. mammal hairs, generate friction when they are mechanically treated, e.g. when they are combed, brushed or rubbed. The generation of friction varies depending on the properties the fibers, the state of the fibers. Usually, the smoother the fibers are and the lower the friction generated upon combing, brushing or rubbing. Likewise, untidy and/or entangled fibers tend to increase the friction generated upon mechanical treatment. The friction generated may also vary depending on the method used for mechanically treating the fibers, and/or the device used for mechanically treating the fibers. The friction generated may vary depending on the number of time and the frequency at which the fibers are combed, brushed or rubbed. The friction may also vary depending on the device used for mechanically treating the fibers, e.g. using a comb comprising close tines is likely to generate a higher friction than a comb comprising spaced tines.
Smoothness of hair is usually associated with the quality of hair but also their degree of damage. The smoothness of hair is reduced when hair are damaged. Hair may be damaged by excessive washing, by treating hair with an inappropriate hair care composition, by exposing them to detrimental environmental conditions, e.g. pollution, sun, rain. Hair may also be damaged following bleaching, perming and/or coloring. This reduction in smoothness is believed to result from changes in the structure of the cuticle, the outermost part of the hair fiber. The more damaged hair are and the more friction generated upon mechanical treatment. In contrast, treating hair with a hair care composition, particularly a hair conditioning composition, aims at increasing hair smoothness and at reducing the friction generated upon mechanical treatment. Reducing the friction generated upon mechanical treatment is preferable as it limits the damages induced by the mechanical treatment itself, i.e. by combing hair, and as it eases the experience of mechanically treating hair.
The consumers and/or users are concerned of having smooth and undamaged hair. The degree of damage may be merely assessed by consumers and/or users by looking and/or touching their hair. However, these methods are subjective and provide little information about the degree and the type of damage. The degree of smoothness may also be assessed by using a combing test in which the force required to detangle, by passing a comb device through hair, is assessed. The degree of damage may also be assessed by methods allowing inspection of hair structure, e.g. microscopy. The degree of damage may be also assessed by methods for assessing the friction properties of hairs. See for example U.S. Pat. No. 6,817,222. However, these methods usually require many types of equipment and provide data to be interpreted by the skilled person, while being barely understandable for consumers and/or users. In contrast, there is a need for a method allowing a direct visualization of the friction generated upon mechanical treatment. In other words, there is a need for a method allowing a direct visualization of the degree of hair damages.
In order to prevent and/or to treat hair damage, the consumers and/or users use hair care compositions. Hair care compositions may comprise many different types of components, e.g. conditioning agents. Hair care compositions may prevent hairs from being damaged, e.g. by exposure to detrimental environments. Hair care compositions may also repair damages by creating a protecting layer around hair. Consumers and/or users are usually interested in knowing whether hair compositions are efficient for preventing and/or treating hair damages. There is a need, therefore, for a method allowing an accurate assessment of the efficacy of a hair care composition for minimizing the friction generated upon mechanical treatment of hair, and so for preventing and/or treating hair damage. There is a need, also, for a method allowing a direct visualization of the efficacy of a hair care composition for minimizing the friction generated upon mechanical treatment of hair. In other words, there is a need for a method allowing a direct visualization of the efficacy of a hair care composition for preventing and/or treating hair damage.
Many different types of hair care compositions are available onto the market. Consumers and/or users are interested in understanding and selecting the compositions having the greater efficacy for preventing and/or treating hair damage. There is a need, therefore, for a method allowing an accurate comparison between the efficacy of hair care compositions for minimizing the friction generated upon mechanical treatment of hair, and so for preventing and/or treating hair damages. There is a need, therefore, for a method for comparing the efficacy of hair care compositions for minimizing the friction generated upon mechanical treatment of hair. In other words, there is a need for a method for comparing the efficacy of hair care compositions for preventing and/or treating hair damages.
In addition, there is a need for a method which can be easily understood by the non-skilled person, including the consumer and/or the end user. There is also a need for a method for supporting advertising claims about the efficacy of a hair care composition for minimizing the friction generated upon mechanical treatment of hair and, therefore, for preventing and/or treating hair damages. There is also a need for a method for supporting advertising claims about the comparison of the efficacy of at least two hair care compositions for minimizing the friction generated upon mechanical treatment of hair and, therefore, for preventing and/or treating hair damages. Finally, there is a need for a method of marketing a hair care composition, which composition is capable of minimizing the friction generated upon mechanical treatment of hair and, therefore, is capable of preventing and/or treating hair damages.